PRESSING OF ORES 



117 



inches wide despatches 4 tons per hour, the grains varying in size from 2 to 4 milli- 

 meters. The size of stuff which can be treated per machine is 1 to 2, 2 to 4, 4 to 8, 

 and 8 to 11 millimeters. 



The fine sand jigger shown in figs. 695 and 696 is designed for the enrichment of 

 sand from \ to 1 millimeter in diameter. The hutch is divided for 2 pistons, and a 



695 



corresponding number of sieves. Compartments are formed underneath the sieves for 

 receiving ore and orey stuff. The overhead gear consists of a shaft, driving wheels, and 

 discs, the latter slotted for piston rod-pins. The pistons are hung so as to balance 

 each other, and when 2 jiggers are employed the pistons of each are worked back to 

 back. The discharged launders are not shown, but these deliver into a main launder 

 set between the two hutches. 

 Fig. 696 is a section through the first piston and second sieve ; fig. 695, a front ele- 



696 



vation, cross section of liutch, and elevation of driving gear, a, hutch, 10 feet long, and 

 2| feet wide; b, piston, 5 feet long and 15 inches wide; c, sieve bottom of iron wire, 

 supported on a wrought-irpn grid, and held down by wrought-iron cross-bars ; d, cast- 

 iron head gear frame ; e, jigger shaft ; p, discs ; g, driving rigger ; h, driving wheel ? - 



